<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<style type="text/css">
			div{
				background-color: #0000FF;width: 50px;height: 50px;animation:3s mn infinite ;
			}
			@keyframes mn{
				0%{
					margin: 0;
				}
				50%{
					margin-top: 60px;
				}
				100%{
					margin-top: 0px;
				}
			}
		</style>
	</head>
	<body>
		<div style="">
			
		</div>
	</body>
</html>
